<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var str = '123'

        var num = 123
        //==比值  ===比类型
        console.log(str===num)

        console.log(str!=num)//false

        console.log(str!==num)//true

        //或与非

        console.log(num<200&&str=='123')

        num<200&&console.log('success')
    </script>
</body>
</html>